When transmitting data on a high-order modulation transmission link, e.g. an M-QAM or M-PSK transmission link (M-QAM: M-level Quadrature Amplitude Modulation; M-PSK: M-level Phase Shift Keying), it is a known technique to use multilevel coding in order to protect the transmitted data with respect to imperfections of the transmission link or transmission equipment. In a multilevel coding scheme, an individual component code is provided for each bit of the data symbols. As the component codes can be individually selected, a good tradeoff between robustness of the data transmission and efficient use of the capacity of the transmission link can be achieved. That is to say, the multilevel coding scheme may be tailored to the requirements of the intended application by suitably selecting the individual component codes.
However, even when using multilevel coding, certain types of disturbances such as strong variations in the characteristics of the transmission channel during an ongoing transmission or phase jitter may adversely affect the transmission performance.
Accordingly, there exists a need to provide improved techniques for data transmission on a high-order modulation transmission link.